Stack light



FIG. 1 is a top front perspective view of a stack light showing our new design.

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a left side elevation view thereof;

FIG. 5 is a right side elevation view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The stack light is shown with a symbolic break in its length, as illustrated by the dot-dash broken lines. The appearance of any portion of the article between the dot-dash broken lines forms no part of the claimed design. The dot-dot-dash broken line shown within the stack light represents the bounds of the claim and forms no part of the claimed design. All other broken lines illustrate environmental structure and form no part of the claimed design. 

CLAIM The ornamental design for a stack light, as shown and described. 